Crossland, of Padside Green Farm, had previously admitted three counts of making indecent images between January 2011 and October 2018.

The images found at his home - 34,612 of which were in the most extreme category A - were described by the Crown Prosecution Service as one of the largest known collections in England and Wales.

The court heard how officers executed a search warrant of his home and found SD cards, USB sticks, DVDs, SIM cards, floppy disks, laptops, tablets and mobile phones containing the images.

Prosecutor Stephen Wood explained how Crossland had "painstakingly categorised" the pictures and some dated as far back as 1988.

This implied he had a "longstanding interest in children", Mr Wood said.

Image copyrightNorth Yorkshire PoliceImage caption
Banned firearms were found in the bunker beneath the Harrogate farmhouse

The underground bunker was fitted with a shooting range and an area designed for the manufacture of ammunition.

The court heard Crossland's wife had answered the door when officers arrived, while the defendant was on a shooting holiday in Argentina.

He was arrested at Heathrow Airport and when interviewed repeatedly gave "no comment" answers.

The judge was told the former business manager, who ran a company that manufactured electronic components for vehicles, had an "arsenal of weapons" and about 24,000 rounds of ammunition.

Crossland pleaded guilty to six charges of possessing prohibited firearms, two of possessing firearms without the relevant certificate, two of possessing ammunition without the relevant certificate, and one of possessing a shotgun without the relevant certificate.

Susannah Proctor, defending, said Crossland had an enthusiasm for weapons dating back to him being given a firearms licence in the 1970s.